As the semiconductor industry has progressed into nanometer technology process nodes in pursuit of higher device density, higher performance, and lower costs, challenges from both fabrication and design have resulted in the development of three dimensional designs, such as fin-like field effect transistors (FinFETs). A finFET is a FET in which the transistor channel is a semiconducting “fin.” For instance, the gate dielectric and gate may be positioned on both sides of the fin such that current flows down the channel on the two sides of the fin. FinFETs allow superior channel charge control even at extremely short gate lengths.
In the future technological nodes of FinFETs, Ge is likely to take an important place as a substitute for Si for the channel formation. This change will however be accompanied by notable fabrication challenges. In particular, creating contacts on a source and/or drain comprising Ge and in particular strained Ge presents considerable challenges due in part to the difficulty to establish such contacts without damaging the geometry of the said source and/or drain. Damages to the geometry of the source and/or drain may lead to increased contact resistivity, lower on/off ratio and/or channel damage in subsequent processing steps. There is therefore a need in the art for processes enabling the formation of contacts with minimal damages to the contact region.